This post describes how to build a scatter plot with tooltips in d3.js. Note that if you don't know anything about tooltips, you probably see the dedicated page of the gallery that will lead you through the basics of this technique. This example works with d3.js v4 and v6
<!DOCTYPE html>
<meta charset="utf-8">
<!-- Load d3.js -->
<script src="https://d3js.org/d3.v4.js"></script>
<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>
<!DOCTYPE html>
<meta charset="utf-8">
<!-- Load d3.js -->
<script src="https://d3js.org/d3.v6.js"></script>
<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>
<script>
// set the dimensions and margins of the graph
var margin = {top: 10, right: 30, bottom: 30, left: 60},
width = 460 - margin.left - margin.right,
height = 450 - margin.top - margin.bottom;
// append the svg object to the body of the page
var svg = d3.select("#my_dataviz")
.append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform",
"translate(" + margin.left + "," + margin.top + ")");
//Read the data
d3.csv("https://raw.githubusercontent.com/holtzy/data_to_viz/master/Example_dataset/2_TwoNum.csv", function(data) {
// Add X axis
var x = d3.scaleLinear()
.domain([0, 3000])
.range([ 0, width ]);
svg.append("g")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x));
// Add Y axis
var y = d3.scaleLinear()
.domain([0, 400000])
.range([ height, 0]);
svg.append("g")
.call(d3.axisLeft(y));
// Add a tooltip div. Here I define the general feature of the tooltip: stuff that do not depend on the data point.
// Its opacity is set to 0: we don't see it by default.
var tooltip = d3.select("#my_dataviz")
.append("div")
.style("opacity", 0)
.attr("class", "tooltip")
.style("background-color", "white")
.style("border", "solid")
.style("border-width", "1px")
.style("border-radius", "5px")
.style("padding", "10px")
// A function that change this tooltip when the user hover a point.
// Its opacity is set to 1: we can now see it. Plus it set the text and position of tooltip depending on the datapoint (d)
var mouseover = function(d) {
tooltip
.style("opacity", 1)
}
var mousemove = function(d) {
tooltip
.html("The exact value of<br>the Ground Living area is: " + d.GrLivArea)
.style("left", (d3.mouse(this)[0]+90) + "px") // It is important to put the +90: other wise the tooltip is exactly where the point is an it creates a weird effect
.style("top", (d3.mouse(this)[1]) + "px")
}
// A function that change this tooltip when the leaves a point: just need to set opacity to 0 again
var mouseleave = function(d) {
tooltip
.transition()
.duration(200)
.style("opacity", 0)
}
// Add dots
svg.append('g')
.selectAll("dot")
.data(data.filter(function(d,i){return i<50})) // the .filter part is just to keep a few dots on the chart, not all of them
.enter()
.append("circle")
.attr("cx", function (d) { return x(d.GrLivArea); } )
.attr("cy", function (d) { return y(d.SalePrice); } )
.attr("r", 7)
.style("fill", "#69b3a2")
.style("opacity", 0.3)
.style("stroke", "white")
.on("mouseover", mouseover )
.on("mousemove", mousemove )
.on("mouseleave", mouseleave )
})
</script> <script>
// set the dimensions and margins of the graph
const margin = {top: 10, right: 30, bottom: 30, left: 60},
width = 460 - margin.left - margin.right,
height = 450 - margin.top - margin.bottom;
// append the svg object to the body of the page
const svg = d3.select("#my_dataviz")
.append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform",
`translate(${margin.left}, ${margin.top})`);
//Read the data
d3.csv("https://raw.githubusercontent.com/holtzy/data_to_viz/master/Example_dataset/2_TwoNum.csv").then( function(data) {
// Add X axis
const x = d3.scaleLinear()
.domain([0, 3000])
.range([ 0, width ]);
svg.append("g")
.attr("transform", `translate(0, ${height})`)
.call(d3.axisBottom(x));
// Add Y axis
const y = d3.scaleLinear()
.domain([0, 400000])
.range([ height, 0]);
svg.append("g")
.call(d3.axisLeft(y));
// Add a tooltip div. Here I define the general feature of the tooltip: stuff that do not depend on the data point.
// Its opacity is set to 0: we don't see it by default.
const tooltip = d3.select("#my_dataviz")
.append("div")
.style("opacity", 0)
.attr("class", "tooltip")
.style("background-color", "white")
.style("border", "solid")
.style("border-width", "1px")
.style("border-radius", "5px")
.style("padding", "10px")
// A function that change this tooltip when the user hover a point.
// Its opacity is set to 1: we can now see it. Plus it set the text and position of tooltip depending on the datapoint (d)
const mouseover = function(event, d) {
tooltip
.style("opacity", 1)
}
const mousemove = function(event, d) {
tooltip
.html(`The exact value of<br>the Ground Living area is: ${d.GrLivArea}`)
.style("left", (event.x)/2 + "px") // It is important to put the +90: other wise the tooltip is exactly where the point is an it creates a weird effect
.style("top", (event.y)/2 + "px")
}
// A function that change this tooltip when the leaves a point: just need to set opacity to 0 again
const mouseleave = function(event,d) {
tooltip
.transition()
.duration(200)
.style("opacity", 0)
}
// Add dots
svg.append('g')
.selectAll("dot")
.data(data.filter(function(d,i){return i<50})) // the .filter part is just to keep a few dots on the chart, not all of them
.enter()
.append("circle")
.attr("cx", function (d) { return x(d.GrLivArea); } )
.attr("cy", function (d) { return y(d.SalePrice); } )
.attr("r", 7)
.style("fill", "#69b3a2")
.style("opacity", 0.3)
.style("stroke", "white")
.on("mouseover", mouseover )
.on("mousemove", mousemove )
.on("mouseleave", mouseleave )
})
</script>